import { defined } from '../../Util/defined';

let a: any;

/**
 * Given a URL, determine whether that URL is considered cross-origin to the current page.
 *
 * @private
 */
function isCrossOriginUrl (url: string): boolean {
    if (!defined(a)) {
        a = document.createElement('a');
    }

    // copy window location into the anchor to get consistent results
    // when the port is default for the protocol (e.g. 80 for HTTP)
    a.href = window.location.href;

    // host includes both hostname and port if the port is not standard
    const host = a.host;
    const protocol = a.protocol;

    a.href = url;
    // IE only absolutizes href on get, not set
    // eslint-disable-next-line no-self-assign
    a.href = a.href;

    return protocol !== a.protocol || host !== a.host;
}
export { isCrossOriginUrl };
